A study examines the extent of wing flapping in Andean condors during flight. Flapping during flight incurs high energy costs for large birds. However, the conditions under which large birds flap their wings are unclear. Emily Shepard and colleagues examined how the Andean condor, the heaviest known soaring bird, can fly with limited flapping. The authors equipped eight immature condors in the Andes near Bariloche, Argentina with biologging devices in multiple field seasons from 2013 to 2018. The birds flapped for 1.3% of the total recorded flight time and spent the rest of the time gliding and soaring. One bird flew continuously for more than 5 hours, covering more than 170 km without flapping. More than 70% of flapping was associated with takeoffs, highlighting the importance of this phase for the total flight costs in Andean condors. Flapping was also most frequent in early morning, when thermal updrafts begin to form and the air rises slowly. The authors predicted that even during winter, when soaring conditions are poor, Andean condors may flap for no more than approximately 2 seconds per kilometer. The findings provide potential insight into how large, extinct animals possibly flew long distances by soaring rather than wing flapping, according to the authors.
Article #19-07360: "Physical limits of flight performance in the heaviest soaring bird," by H.J. Williams et al.
MEDIA CONTACT: Emily Shepard, Swansea University, UNITED KINGDOM; tel: +44 7899997424, 01792-604001; e-mail: e.l.c.shepard@swansea.ac.uk
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Proceedings of the National Academy of Sciences